#include<stdio.h>
int main()
{
	int a;
	printf("请输入成绩：");
	while(scanf("%d",&a)!=EOF)
	{
	if(a>=90)
		printf("A\n");
	    else if(a>=80&&a<=89)
		printf("B\n");
		else if(a>=70&&a<=79)
			printf("C\n");
		else if(a>=60&&a<=69)
			printf("D\n");
		else if(a<=60&&a>=0)
			printf("E\n");
    } 	
	return 0;
}
